The invention relates to the production of stable solutions of rare earth tris (organophosphates) in a hydrocarbon solvent.
The production of rare earth tris (organophosphates), particularly rare earth alkylphosphates, in various solvents is generally a straightforward process. Due to their low solubility in water and common organic solvents, the rare earth tris (organophosphates) precipitate easily. The poor solubility of these compositions is noted in the article, xe2x80x9cDEHP complexes of lanthanides (III) and actinides (III),xe2x80x9d Suglobov et al., Journal of Alloys and Compounds, 213/214 (1994) 523-527. Suglobov et al. point out that xe2x80x9cLnA3 (A=dialkylphosphate) is very poorly soluble in alkanes as well as in donor solvents.,xe2x80x9d See the Abstract page 523 of Suglobov et al. The lower solubility of the rare earth tris (organophosphates) in hydrocarbon solvents, compared to, for instance, rare earth neo acid complexes, is mainly due to the presence of the phosphorous atoms which considerably lowers the organic character of the molecule. Providing rare earth tris (organophosphates) in a hydrocarbon solvent is desirable for manufacturers utilizing the rare earth tris (organophosphates) for preparation of catalysts. If the rare earth tris (organophosphates) could be stable in the hydrocarbon solvent, i.e., not precipitate over an extended period of time, such a product would be very beneficial for the manufacturing formulator.
It is an aspect of the present invention to produce solutions comprising a rare earth tris (organophosphate) and a hydrocarbon solvent wherein said solutions are stable from precipitation of the rare earth tris (organophosphate) for at least about thirty days.
It is another aspect of the present invention to introduce a process, which by a combination of beneficial experimental conditions, allows the production of highly stable solutions of a rare earth tris (organophosphate) in a hydrocarbon solvent.
These and other aspects of the invention are discussed in detail below.
The stable rare earth tris (organophosphate) solutions comprise a rare earth tris (organophosphate) and a hydrocarbon solvent. Preferably, from about 2% to about 10% rare earth element, preferably from about 3% to about 8%, is present in the solutions. Unless otherwise stated, all parts, ratios or percents are by weight. The rare earth tris (organophosphate) solutions are stable from precipitation of the rare earth tris (organophosphate) for at least about fifteen (15) days, preferably for at least about twenty (20) days and most preferably at least about thirty (30) days. A process for preparing these solutions is described herein.
As used herein, xe2x80x9calkylxe2x80x9d means a carbon-containing chain which may be straight, branched or cyclic; substituted (mono- or poly-) or unsaturated; and saturated.
As used herein, xe2x80x9carylxe2x80x9d means an aromatic; substituted (mono- or poly-) or unsaturated.
As used herein, xe2x80x9cfree acidxe2x80x9d means the H+ concentration as measured by conventional methods.
As used herein, the terms xe2x80x9crare earth tris (organophosphate)xe2x80x9d, xe2x80x9corganophosphatexe2x80x9d, xe2x80x9calkylphosphatexe2x80x9d, xe2x80x9cbasexe2x80x9d, xe2x80x9cstabilizing additivexe2x80x9d and xe2x80x9crare earth saltxe2x80x9d shall encompass the singular and plural, as well as, to encompass mixtures of the respective compounds.
xe2x80x9cComprisingxe2x80x9d as used herein, means various components can be conjointly employed. Accordingly, the terms xe2x80x9cconsisting essentially ofxe2x80x9d and xe2x80x9cconsisting ofxe2x80x9d are embodied in the term comprising.